C-type underbracing having enlarged end portions for installing on utility pole

ABSTRACT

A C-type underbracing has developed for installing on a lower portion of a utility pole for firmly anchoring the utility pole. The underbracing is comprised of: a body ( 12 ) formed a half-annular or C-shape with a rectangular cross section; a pair of the enlarged end portions ( 11, 11 ′) having larger rectangular cross section than that of the body; a pair of the conjunction ( 17, 17 ′) for connecting between the body and the enlarged end portions; a hook receiving hole ( 13 ) horizontally through a center of the body, and a pair of nut mounting portions ( 16, 16 ′) formed flat surfaces for seating the nuts and a pair of slit-shaped holes ( 14, 14 ′) for horizontally inserting U-bolts ( 20 ) through the body portion, the nut mounting portions and slit-shaped holes disposed both sides of said hook receiving hole, and an earth plate ( 30 ) made of conductive material is attached to the bottom surface of the body.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a C-type underbracing installed atbottom end of the utility pole for anchoring. More particularly, theC-type underbracing formed enlarged end portions to facilitateinstallation on the utility pole by using a crane auger. The bodysegment between the enlarged end portions is formed C-shape with thinnerthan the body thickness. Thus, the enlarged end portions of the C-typeunderbracing will increase the contacting area with the covered soils toimprove the resistance and enhance the supporting tension to the utilitypole.

2. Description of the Related Art

For example, Korean Patent Application No. 2006-112100, filed by theapplicant of the present invention, discloses a utility poleunderbracing for utility pole construction. In this underbracing, asshown in FIG. 1, the overall shape of the underbracing 100 is roughly ahalf toroid. The inner semi-circle surface 101 conforms to thecross-section shape of a utility pole, and the outer semi-circle 102 hasa diameter of about 0.8 m. Although this underbracing has a shapedifferent from the conventional bar-type utility pole underbracing, thesurface area in contact with soil after mounting is almost the same.

However, the volume is smaller so the weight is less than theconventional rectangular underbracing. Therefore, when excavating thepit for burying the pole during utility pole construction, theexcavation volume is greatly reduced compared to the conventionalrectangular underbracing, and since it is easier to handle, constructionefficiency and workability are improved.

Furthermore, on the outer circumference of the semi-circular utilitypole underbracing there are a U-bolt inserting hole 103 used formounting the underbracing and a slot 104 which increases the cohesionwith soil under the earth surface. The inner circumference varies, madeaccording to the curvature specification of the utility pole, resultingin better installability and increased strength of underbracing.

However, since the above mentioned semi-circular utility poleunderbracing is a C-type solid bound by curved surfaces, the adherencearea with soil is not sufficient, so the coherence between the pole andthe soil is not satisfactory. In the case of assembling with U bolts,the U-bolt insertion hole is of through-hole shape, so the dimensions ofthe insertion hole and the U bolt should match, which causes difficultyin logistics management, and frictional interference in construction.

Also, since the above mentioned conventional semi-circular utility poleunderbracing is relatively large and heavy (95 kg), it is difficult tohandle and there are many difficulties with fabrication andtransportation. When installing a large and heavy object in the utilitypole burial pit by using an extra crane, the process for binding theunderbracing to the crane is complicated, and it is also very difficultand toilsome to disconnect the bindings again.

Therefore, the actual site has dire need for an improved utility poleunderbracing that has better adherence resistance force with the soiland also is easier to fasten to the pole.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a C-typeunderbracing, for installation on a utility pole, wherein there areenlarged portions at both ends of the underbracing and the C-type bodyportion connecting the enlarged portions at both ends through inclinedelements, is constructed smaller than the enlarged portions. The forceof ground contact with the soil is improved through the enlargedportions. The utility pole underbracing is made lighter through the bodyportion being smaller than the enlarged portion. A hook inserting holeis through-formed in the center of the underbracing, so that it is easyto move and put in the utility pole underbracing using a crane. Boltjoining holes of slit shape are formed, separated at a given interval,making it easy to fasten a U bolt through the bolt joining hole.

In accordance with the present invention, there is provided a utilitypole underbracing comprising friction-increasing means, which are:enlarged portions formed at both ends of a monolithically-formed utilitypole underbracing; a C-type body portion with size and weight reduced; abinding guide means; and fastening means which are bolt joining holesfor U bolts installed on the utility pole, formed at both sides of ahook receiving hole.

According to the C-type utility pole underbracing with enlargedportions, for construction of a burial hole for the present invention,the force of contact with the soil is improved by the enlarged portions.The utility pole is made lightweight through a reduced body portion. Itis easy to move and install the utility pole underbracing with a crane,by using the hook receiving holes, and U bolts are fastened easilythrough the bolt joining holes, so there is convenience in construction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a conventional C-type underbracingof prior art.

FIG. 2 is a front perspective view showing a C-type underbracingaccording to the present invention.

FIG. 3 is a rear perspective view showing the C-type underbracingaccording to the present invention.

FIG. 4 is a plan sectional view of the C-type underbracing according tothe present invention.

FIG. 5 is a schematic view showing the process of putting in a C-typeunderbracing in a burial hole according to the present invention.

FIG. 6 is a schematic view showing the construction process of a C-typeunderbracing according to the present invention, and

FIG. 7 is a perspective view showing a C-type underbracing according toanother embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Below will be described a preferred embodiment of the present inventionwith reference to the accompanying drawings.

FIG. 1 is a perspective view showing a conventional C-type underbracingof prior art, FIG. 2 is a front perspective view showing a C-typeunderbracing according to the present invention, FIG. 3 is a rearperspective view showing the C-type underbracing according to thepresent invention, and FIG. 4 is a plan sectional view of the C-typeunderbracing according to the present invention.

In C-type utility pole underbracing 10 according to the preferredembodiment of the present invention, enlarged portions 11 and 11′ withthe size-increased upward and sideward are formed respectively at bothends, and the body portion 12 of the underbracing 10 which connects theenlarged portions 11 and 11′ through the inclined portions 17 and 17′,has a smaller size than the enlarged portions 11 and 11′. In the centerof the utility pole underbracing 10 a hook receiving hole 13 isthrough-formed, and on both sides of the hook receiving hole 13 are boltinserting holes 14 and 14′ of slit shape. Around the hook receiving hole13 of the body portion 12 there is a first friction-increasing slot 15,concave in shape and of a given depth, and around the bolt-insertingholes 14 and 14′ of the body portion 12 there are partly cut-away secondfriction slots 16 and 16′, respectively.

Also, the body portion 12, placed between the enlarged portions 11 and11′ of the utility pole underbracing 10, includes inclined portions 17and 17′ to take a more natural shape and provide excellent durabilityagainst external shock applied to the corner.

The utility pole underbracing 10, according to another embodiment of thepresent invention, further comprises an earthing plate 30 attached tothe bottom surface of the utility pole underbracing 10, and a groundwire 31, one end of which is connected to the earthing plate 30 and theother end of which is drawn out through the body portion 12, so that theground wire 31 is effectively connected to the earth line of the utilitypole. As shown in FIG. 6, the utility pole underbracing 10 is mounted tothe utility pole 21 by U bolt 20.

The process of installation of a utility pole, using a C-type utilitypole underbracing with enlarged portions, will be described in moredetail with reference to the accompanying drawings.

In general, after completing minimum excavation work for burying C-typeutility pole underbracing by using equipment such as an auger crane,backhoe or manpower, the utility pole underbracing 10 is mounted to theutility pole 21 by U bolt 20.

Both ends of the C-type utility pole underbracing 10 of the presentinvention are shaped as enlarged portions 11 and 11′ of size-increasedshape. Since these enlarged portions 11 and 11′ require largely widenedareas of interference and friction with soil due to backfilling, theresultant binding force with soil is increased, so the utility pole 21can be maintained more stably and firmly.

Although proper binding force with soil can be obtained by C-typeunderbracing alone, the utility pole might be inclined or slanted as aresult of soil quality or geologic condition. In such a case,inclination or slant of the utility pole 21 can be prevented by theenhanced binding force with soil of the enlarged portions 11 and 11′ onthe utility pole underbracing of the present invention.

In addition, the utility pole underbracing 10 of the present inventionhas bolt inserting holes 14 and 14′ provided in its body portion 12.These bolt inserting holes 14 and 14′ have a horizontally penetratedslit shape, with an advantage that when assembling U bolt 20 to mountthe utility pole underbracing 10 to the utility pole 21, the U bolt 20can be installed more easily and quickly.

The body portion 12 of a utility pole underbracing 10 according to thepresent invention has a shape of smaller size than the enlarged portions11 and 11′. Since the body portion 12 is smaller, the total weight ofthe utility pole underbracing 10 is reduced greatly and it is easier tohandle and install. In addition, since the enlarged portions 11 and 11′and body portion 12 of utility pole underbracing 10 are connectedsolidly through gentle inclined portions 17 and 17′, the total weight ofthe utility pole underbracing 10 is reduced. Since the increasedadherence area with soil can be maintained as it is, the utility pole 21can be supported more stably.

In the center of the body portion 12 the hook receiving hole 13 isthrough-formed horizontally. As shown in FIG. 5, during the work ofmoving and installing utility pole underbracing 10 using crane 110, theutility pole underbracing 10 can be handled more conveniently byinserting the hook 111 into the hook receiving hole 13, for transportand installation of the utility pole underbracing.

The outer circumference of the body portion 12 is provided with thefirst friction increasing slot 15, formed around the hook receiving hole13, and the second friction increasing holes 16 and 16′, formed aroundthe bolt inserting holes 14 and 14′. Friction resistance strengthbetween the utility pole underbracing 10 and the soil is increasedthrough these first friction slot 15 and second friction slots 16 and16′. The second friction increasing slots 16 and 16′ also createaccommodating spaces where stop nuts fastened to the screw portions of Ubolt 20 are located during use.

The bottom surfaces 18 of the second friction increasing slots 16 and16′ are formed at inclinations of 5° to 10° as they go outward so as toprevent the nuts of the U bolts from adhering to the inner wall of thesecond friction-increasing slots during utility pole underbracinginstallation, to make it easy to use a tool for tightening the nuts. Asthe nut moves outward along the inclined portion when the nut isfastened, the position of the U bolt gradually moves from the inside tothe outside of the bolt inserting holes 14 and 14′ while the surfacecontact portion is increased, so it is possible to fix U bolt firmly andstably.

Therefore, as shown in FIG. 6, the utility pole underbracing 10 mountedon the lower part of the utility pole 21 and buried in soil can getexcellent binding force with soil and can be installed easily.

Meanwhile, the utility pole underbracing according to another embodimentof the present invention has an earthing plate 30 made of metal materialattached on the whole bottom surface of the utility pole underbracing10, and a ground wire 31 connected to the earthing plate 30, as shown inFIG. 7. The ground wire 31 can be used by easily connecting it with theearth line of utility pole, after exposing it outside through the bodyportion 12 of the utility pole underbracing 10.

Although the present invention has been described in detail reference toits presently preferred embodiment, it will be understood by thoseskilled in the art that various modifications and equivalents can bemade without departing from the spirit and scope of the presentinvention, as set forth in the appended claims.

1. A C-type underbracing for installing on bottom of a utility pole,comprising: a body portion (12) formed a half-annular or C-shape with arectangular cross section, a pair of enlarged end portions (11, 11′)having larger rectangular cross section than that of the body portion(12), a pair of conjunction portions (17, 17′) for connecting betweenthe body portion (12) and the enlarged end portions (11, 11′), a hookreceiving hole (13), which are horizontally through a center of the bodyportion, and a pair of nut mounting portions (16, 16′) formed flatsurfaces for seating the nuts and a pair of slit-shaped holes (14, 14′)for horizontally inserting U-bolts (20) through the body portion, saidnut mounting portions (16, 16′) and slit-shaped holes (14, 14′) disposedboth sides of said hook receiving hole (13).
 2. The C-type underbracingas set forth in claim 1, further comprising a hook mounting seat (15)formed a circular-shaped flat area, which is sink-down around the hookreceiving hole (13) for increasing frictional forces.
 3. The C-typeunderbracing as set forth in claim 1, further comprising an earth plate(30) made of conductive material for attaching to bottom surface of thebody portion (12) and a ground wire (31) drawn out from the earth plate(30).
 4. The C-type underbracing as set forth in claim 1, wherein saidnuts and U bolts are prevented adhering to the mounting portions (16,16′) during the installation of underbracing, a seating surface (18) ofthe mounting portions (16, 16′) is inclined 5°˜10° outward for easilytightening the nuts, so that the U bolts and nuts gradually move outwardof the slit-shaped holes (14, 14′).